1. Field of the Invention
The invention relates to a method and system for controlling gaseous or liquid flow in relation to a body that is interposed in the flow path.
2. Background Art
One example of fluid flow in relation to a foil is an air foil (e.g., aileron, flap, rudder, elevator) associated with an aircraft that is interposed in a flow path defined by ambient air. As used herein, the term “fluid” includes gaseous (e.g., air) and liquid matter (e.g. water). In the context of aerodynamics, the background of this invention includes air foils that may be provided on aircraft, automobiles—including race cars—and, in the context of hydrodynamics, hydrofoils that are provided on some boats or amphibious vehicles for influencing their passage through water or air.
The low speeds that small aircraft operate at, especially during take-off, initial climb, and approach to landing, make stall a significant safety concern. When an aircraft enters a stall, it typically rolls. If not corrected, this can lead to an uncontrollable spin. Due to the flow separation of air from a wing at stall, the aileron and rudder controls may be unable to return the aircraft to a level configuration. This situation accounts for the majority of general aviation (GA) accidents.
In either the aerodynamic or hydrodynamic context, the efficiency of fluid flow around an object—sometimes referred to herein as a “foil”—is impeded when there is flow separation between the fluid and the foil. This may occur adjacent areas of an abrupt change in the profile that a foil presents to incident fluid. In such circumstances, it may be desirable to harness energy associated with the incident fluid flow.
It is known that low speed maneuverability is desirable in aircraft, ships and submarines. As noted above, the forces associated with conventional hinged control surfaces (“control authority”) may not be enough to allow certain maneuvers to be performed.